/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
Copyright (C) 2006 Robert Beckebans <trebor_7@users.sourceforge.net>

This file is part of XreaL source code.

XreaL source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

XreaL source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with XreaL source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
//
// trilib.c: library for loading triangles from an Alias triangle file
//

#include <stdio.h>
#include "cmdlib.h"
#include "mathlib.h"
#include "polyset.h"
#include "trilib.h"

// on disk representation of a face


#define	FLOAT_START	99999.0
#define	FLOAT_END	-FLOAT_START
#define MAGIC       123322

//#define NOISY 1

#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
#define strlwr strlower
#endif

typedef struct
{
	float           v[3];
} vector;

typedef struct
{
	vector          n;			/* normal */
	vector          p;			/* point */
	vector          c;			/* color */
	float           u;			/* u */
	float           v;			/* v */
} aliaspoint_t;

typedef struct
{
	aliaspoint_t    pt[3];
} tf_triangle;


static void ByteSwapTri(tf_triangle * tri)
{
	int             i;

	for(i = 0; i < sizeof(tf_triangle) / 4; i++)
	{
		((int *)tri)[i] = BigLong(((int *)tri)[i]);
	}
}

static void ReadPolysetGeometry(triangle_t * tripool, FILE * input, int count, triangle_t * ptri)
{
	tf_triangle     tri;
	int             i;

	for(i = 0; i < count; ++i)
	{
		int             j;

		fread(&tri, sizeof(tf_triangle), 1, input);
		ByteSwapTri(&tri);
		for(j = 0; j < 3; j++)
		{
			int             k;

			for(k = 0; k < 3; k++)
			{
				ptri->verts[j][k] = tri.pt[j].p.v[k];
				ptri->normals[j][k] = tri.pt[j].n.v[k];
//              ptri->colors[j][k] = tri.pt[j].c.v[k];
			}

			ptri->texcoords[j][0] = tri.pt[j].u;
			ptri->texcoords[j][1] = tri.pt[j].v;
		}

		ptri++;
		if((ptri - tripool) >= POLYSET_MAXTRIANGLES)
			Error("Error: too many triangles; increase POLYSET_MAXTRIANGLES\n");
	}
}

void TRI_LoadPolysets(const char *filename, polyset_t ** ppPSET, int *numpsets)
{
	FILE           *input;
	float           start;
	char            name[256], tex[256];
	int             i, count, magic, pset = 0;
	triangle_t     *ptri;
	polyset_t      *pPSET;
	int             iLevel;
	int             exitpattern;
	float           t;

	t = -FLOAT_START;
	*((unsigned char *)&exitpattern + 0) = *((unsigned char *)&t + 3);
	*((unsigned char *)&exitpattern + 1) = *((unsigned char *)&t + 2);
	*((unsigned char *)&exitpattern + 2) = *((unsigned char *)&t + 1);
	*((unsigned char *)&exitpattern + 3) = *((unsigned char *)&t + 0);

	if((input = fopen(filename, "rb")) == 0)
		Error("reader: could not open file '%s'", filename);

	iLevel = 0;

	fread(&magic, sizeof(int), 1, input);
	if(BigLong(magic) != MAGIC)
		Error("%s is not a Alias object separated triangle file, magic number is wrong.", filename);

	pPSET = calloc(1, POLYSET_MAXPOLYSETS * sizeof(polyset_t));
	ptri = calloc(1, POLYSET_MAXTRIANGLES * sizeof(triangle_t));

	*ppPSET = pPSET;

	while(feof(input) == 0)
	{
		if(fread(&start, sizeof(float), 1, input) < 1)
			break;
		*(int *)&start = BigLong(*(int *)&start);
		if(*(int *)&start != exitpattern)
		{
			if(start == FLOAT_START)
			{
				/* Start of an object or group of objects. */
				i = -1;
				do
				{
					/* There are probably better ways to read a string from */
					/* a file, but this does allow you to do error checking */
					/* (which I'm not doing) on a per character basis.      */
					++i;
					fread(&(name[i]), sizeof(char), 1, input);
				} while(name[i] != '\0');

				if(i != 0)
					strncpy(pPSET[pset].name, name, sizeof(pPSET[pset].name) - 1);
				else
					strcpy(pPSET[pset].name, "(unnamed)");
				strlwr(pPSET[pset].name);

//              indent();
//              fprintf(stdout,"OBJECT START: %s\n",name);
				fread(&count, sizeof(int), 1, input);
				count = BigLong(count);
				++iLevel;
				if(count != 0)
				{
//                  indent();
//                  fprintf(stdout,"NUMBER OF TRIANGLES: %d\n",count);

					i = -1;
					do
					{
						++i;
						fread(&(tex[i]), sizeof(char), 1, input);
					} while(tex[i] != '\0');

/*
					if ( i != 0 )
						strncpy( pPSET[pset].texname, tex, sizeof( pPSET[pset].texname ) - 1 );
					else
						strcpy( pPSET[pset].texname, "(unnamed)" );
					strlwr( pPSET[pset].texname );
*/

//                  indent();
//                  fprintf(stdout,"  Object texture name: '%s'\n",tex);
				}

				/* Else (count == 0) this is the start of a group, and */
				/* no texture name is present. */
			}
			else if(start == FLOAT_END)
			{
				/* End of an object or group. Yes, the name should be */
				/* obvious from context, but it is in here just to be */
				/* safe and to provide a little extra information for */
				/* those who do not wish to write a recursive reader. */
				/* Mea culpa. */
				--iLevel;
				i = -1;
				do
				{
					++i;
					fread(&(name[i]), sizeof(char), 1, input);
				} while(name[i] != '\0');

				if(i != 0)
					strncpy(pPSET[pset].name, name, sizeof(pPSET[pset].name) - 1);
				else
					strcpy(pPSET[pset].name, "(unnamed)");

				strlwr(pPSET[pset].name);

//              indent();
//              fprintf(stdout,"OBJECT END: %s\n",name);
				continue;
			}
		}

//
// read the triangles
//      
		if(count > 0)
		{
			pPSET[pset].triangles = ptri;
			ReadPolysetGeometry(pPSET[0].triangles, input, count, ptri);
			ptri += count;
			pPSET[pset].numtriangles = count;
			if(++pset >= POLYSET_MAXPOLYSETS)
			{
				Error("Error: too many polysets; increase POLYSET_MAXPOLYSETS\n");
			}
		}
	}

	*numpsets = pset;

	fclose(input);
}
